Southern Lakes Caribou Recovery Program

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	Introduction
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	Woodland Caribou
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Southern Lakes Caribou Recovery Program
Progress Report: 1992-1996

Woodland Caribou

Woodland caribou, such as those in the Southern Lakes region, do not undergo long seasonal migrations in large herds, as do the smaller barren ground caribou to the north. Rather, depending on the local conditions, they move variable distances between habitats that offer them safe calving grounds, good summer ranges that allow respite from insects, and winter ranges with adequate food and low snow cover.

Season:	Conditions:	Events:	Habitats:	Hazards:
Spring Migration (April-May)	snow melting days getting longer	caribou moving from lowlands	caribou moving into mountains	falling through thin ice and drowning crossing highways fences and large clearings blocking migration routes
Calving (May 27-June 5)	warmer temperatures patchy snow still present in alpine	cows give birth to single calf in isolation secluded calving sites chosen to minimize chances of predation	calving on rugged alpine ridges with up to 50% snow cover cows are dispersed 1-2 per mountain top over a wide area	wolves, grizzly bears, coyotes and golden eagles all prey on newborn calves
Calf Care (June-August)	long warm days thick mosquitoes	caribou feed in areas of late snow-melt on greening-up forbs, grasses and sedges - nutrient rich and necessary for milk production willows mostly eaten in July caribou move between mountains looking for food	caribou seek patches of snow, glaciers and windy ridges to escape insects	harassment by insects hunting predation by wolves
Rutting (Sept.-Oct.)	early snowfalls, caribou in prime condition	caribou form large mixed-sex groups in rutting grounds	alpine and sub-alpine areas	hunting predation by wolves bulls lose weight and may injure each other during fights
Fall Migration (Nov.-early Dec.)	beginning of winter with permanent snow	snow and weather prompt caribou to move out of the mountains	caribou move into valley bottoms	falling through thin ice and drowning fences blocking migration routes crossing highways
Winter (mid Dec.-March)	short days cold temperatures deepening snow depths, and crusts	caribou dig through snow for food - mostly lichens and some evergreen plants (winter green) caribou move less and lose weight as snow gets deeper	forested valley bottoms near Whitehorse with low snow cover and abundant lichens Ibex region caribou winter in subalpine near Mud Lake	food shortage hunting harassment by snowmobiles and dogs causing overheating crossing highways predation by wolves

Lichens

Lichens, or "caribou moss", are found on the forest floor and clinging to rocks, and while they're easily overlooked, they make up about 70% of the winter diets of caribou. Lichens are composed of two distinct parts, a fungus and an alga, which grow together and cooperate to extract nutrients from rocks, soil and the air. While many plants prefer rich soils, most lichens are actually found in poorer habitats, where they don't face as much competition for food from other plants.

Caribou migrate to reach their winter ranges and concentrate in very specific areas. The key to their winter needs appears to be access to lichens. When snow depths exceed about 60 cm (2 feet), or hard-packed crusts develop, caribou have difficulty locating and digging down to the ground-dwelling lichens.

In the Southern Lakes region, the best winter habitat for the caribou is in the mature forests, 50-200 years old, where lichens are most abundant and the snow is usually powdery. The area around Marsh Lake, in the rain shadow of the Coast Mountains, is ideal winter habitat for caribou.

While lichens are extremely nutritious, they are also very small and slow-growing. Lichens grow approximately one centimeter every ten years. Caribou require 3-5 kilograms, or about 2 large garbage bags full, of lichens per day during the winter. Even in the best habitats, the cover of lichens is usually sparse, but caribou are able to smell them through the snow with their sensitive noses. In order to get at them, caribou dig "craters" with their large hooves, crop the lichens there, and move on. They feed mostly during the morning and evening, and may spend up to a third of their time trying to find enough food. As snow depths get deeper towards the end of winter, caribou restrict their movements more and more, and they often lose weight during this time.

The availability of habitats that have the right combination of shallow, powdery snow and abundant lichens that makes good caribou winter range is very limited. Even in areas where the snow conditions are right, fires or logging can eliminate lichen growth until forest cover returns. Maintaining these winter ranges is absolutely critical to the long-term survival of the caribou.